Fairings are often present in the inlet case of aircraft turbofan engines. A fairing is generally bonded to and surrounds and protects an inner strut or other similar structural element within the inlet case. Each inner strut generally extends from a central inner ring to an outer diameter ring of the inlet. Each fairing typically surrounds the full radial length of the inner strut. Composite fairings typically consist of several layers of fiberglass or other materials, bonded together to form the fairing structure. Each fairing has a closed and generally rounded upstream end. From the upstream end, two fairing sides extend downstream and around the inner strut. The sides of the fairing are bonded to sides of the inner strut and continue downstream to form two downstream ends. Fairings and inner struts are generally located upstream of the compressor, combustion, and turbine sections of the turbofan. In some turbofans, the fairings contain sensors and heating elements to prevent the formation of ice within the inlet case and to de-ice areas of the inlet case.
During operation of the turbofan and during flight, a fairing or its heating elements may become damaged or inoperable. Damage to the fairing or the heating elements may occur due to events such as a bird strike. Inoperability may result because of wear or malfunction. When significant damage to a fairing or its heating elements occurs or the heating elements no longer function properly, the fairing is normally removed and replaced.
Removing a fairing from the inner strut to which it is bonded can be an arduous task for an aircraft mechanic or operator. In order to remove a fairing from an inner strut, the bond between the two components must be released. Typically, a silicone compound is used to bond the fairing and inner strut. The bondline between the fairing and inner strut typically extends the full length of the inner strut (along the turbofan's longitudinal axis) and roughly two-thirds the length of the fairing (along the same axis). This bondline generally extends the full radial length of the fairing and inner strut. Due to the relatively large surface area of the bond and the strength of the bond needed to ensure adequate binding during flight, releasing the bond can be quite difficult.
Until now, removing a fairing has been difficult. A large number of inner struts extend from the nosecone to the outer diameter ring, usually more than a dozen. This configuration of multiple inner struts and fairings, as well as components farther downstream, makes for small spaces within the inlet case and prevents the use of large tools. Typically, a screwdriver type prybar or a similar small tool was used to pry the fairing away from the inner strut. A utility knife or other small blade was then used to cut away at the bondline. This method of releasing the bond had several faults. First, screwdriver type prybars generally have a limited thickness and an operator would need to pry many times along the radial length of the fairing in order to release the fairing-strut bond. On occasion, an operator would need to pry multiple times in a small area to fully release even a portion of the bond. A typical operator might spend fifteen or more minutes using this method to remove a single fairing. Additionally, due to the time necessary to remove the fairing and the awkward angle at which the operator needed to use a prybar to pry apart the bond, fairing removal was performed only while the operator was on the ground. Second, an operator would have to reach a good distance beyond the downstream ends of the fairing in order to position the screwdriver type prybar to adequately pry. In some instances, this would require the additional removal of downstream components, such as the first set of compressor vanes, before a fairing could be removed. The downstream components would then need to be replaced once the fairing was removed. This increased the time needed to remove and replace a fairing. Third, damage to the inner strut would sometimes result from the use of a prybar to pry the fairing from the strut. When damage to the inner strut occurred, the inner strut would then need to be repaired or replaced.
Prior fairing removal methods and tools did not meet the needs of aircraft mechanics and operators. Thus, there is still a need for a faster and more efficient method of removing a fairing from an inlet case and still a need for a useful tool to facilitate such a method.